1. Field of the Invention
The present invention relates to an inspection support apparatus and an inspection support method, and more specifically to an inspection support apparatus and an inspection support method suitable for use in a debugging system for inspecting a system employing a microcomputer.
2. Description of the Related Art
When debugging a system employing a microcomputer, a variety of data output from the microcomputer is monitored by a monitoring unit so as to confirm the operating state of the microcomputer. For example, to confirm a program execution state performing a data access to a particular address by means of the microcomputer, the monitoring unit monitors an access state to the particular address using a data passing through a data bus of the microcomputer, a trace data output from the microcomputer, etc., so as to confirm whether or not the data access intended by the program is actually performed.
In particular, to detect a trouble which may occur with extremely low frequency, there is a frequently used debugging method such as executing a program for a long time, and monitoring data continuously during the program execution. In this case, since the acquired amount of the monitored data becomes large in proportion to the measurement time, processing for restricting the data amount is also performed by acquiring the monitored data at appropriate sampling intervals.
However, the microcomputer executes an arithmetic operation and a data access based on an internal reference clock. Therefore, on the occurrence of a state such as suspending of the reference clock in the microcomputer (for example, reset state, stop state, power off state, etc.), it becomes impossible to acquire information to be monitored, because there is no data output from the microcomputer.
As a result, in the conventional monitoring unit, there has been a problem such that, when it is intended to monitor data in regard to a program execution for a time duration internally containing a period such as a state of suspension of the reference clock of the microcomputer, the monitored data acquired from the microcomputer only before and after the above reference clock suspension period is not sufficient for acquiring data for a net measurement time, because no monitored data exists during the clock suspension. Also, there has been another problem such that, because the reference clock suspension of the microcomputer is not preserved as the monitored data, it is not possible to identify a reference clock suspension point by analyzing the monitored data acquired above, in the monitoring unit in which the reference clock suspension state of the microcomputer is not taken into consideration.
Further, in the patent document 1 shown below, in an in-circuit emulator, there has been disclosed a time measurement circuit and a time measurement method for measuring the execution time of a target program to be emulated, and for preserving the measured execution time correspondingly to a traced data.
[Patent document 1] Japanese Patent Application Laid-open No. 2001-92692